Application of 2-D Finite-Element Fluid-Flow Model to Thermal Histories in Thrust Belts

Abstract

A new two-dimensional finite-element fluid-flow model enables the thermal effects of overthrusting to be analyzed with a considerably higher degree of accuracy than with previously applied one or two-dimensional models. Test cases are subjected to sensitivity analyses in order to indicate the effects and relative importance of parameters such as thrust sheet thicknesses, movement rates, fault angles, lithology types, and erosion, as well as the relative importance of conductive and convective heat transport within the thrusted sequence. The calculated thermal histories are then used for calibration parameters such as vitrinite reflectance, as well as for a determination of hydrocarbon generation, expulsion, and migration histories. The results clearly show the potential errors inherent to one-dimensional modeling of thermal histories thrust belts and enable a quantification of the effects on hydrocarbon generation histories. They also indicate the superior capabilities of finite-element methods for integrated analyses of structural, thermal, and hydrocarbon generation histories in complex geological environments.